Conventionally, for example, JP-A-2003-189291 and JP-A-2006-7498 disclose an art for indicating a composite view by combining an image, which is obtained by imaging a peripheral condition of a rear side of a self-vehicle in real time, with both an image indicating a view, which is moved to the outside of a view area while the self-vehicle moves rearward, and an image of the self-vehicle. Thus, a physical relationship between the self-vehicle and the peripheral condition are provided to a driver.
According to the first conventional art described in JP-A-2003-189291, images obtained by using a camera is, for example, converted into data in coordinates of the ground surface projected in a viewpoint of a camera so as to successively produce image data of birds-eye view images. Accordingly, the indicated image is not a distorted image specific to a raw image. Subsequently, a first birds-eye view image, which is obtained in the previous imaging, is moved correspondingly to a movement of the vehicle so as to produce image data of the birds-eye view image after the movement of the vehicle. The image data of the birds-eye view image after the movement of the vehicle is combined with image data of a second birds-eye view image, which is newer than the first birds-eye view image, so as to produce a composite birds-eye view image. Further, the composite birds-eye view image is converted to a projection image, which looks like being obtained by a camera, and the projection image is indicated on a monitor device or the like.
According to the second conventional art disclosed in JP-A-2006-7498, a graphic processing unit corrects distortional aberration in present image data and previous image data caused by a wide-angle lens so as to obtain an image without distortion. Further, the graphic processing unit extracts only a part of the corrected previous image data on the vehicle side so as to obtain previous data for a composite image. Further, a viewpoint of the previous data for a composite image is converted to a viewpoint from an imaginary viewpoint on the upper side of a center of a rear wheel axle. Further, the graphic processing unit extracts only a part of the corrected present image data on a side farther from the vehicle so as to obtain present data for a composite image. Further, the graphic processing unit performs reduction conversion to reduce the present data for a composite image at a predetermined reduction ratio so as to produce reduced data. Subsequently, the graphic processing unit produces a composite image by combining the reduced data with a composite region of the previous data for a composite image, which is converted in the viewpoint, and outputs the produced composite image on a screen of a display device. Further, the graphic processing unit converts extension lines of the lateral sides of the vehicle and lines drawn by rear wheels according to the imaginary viewpoint and outputs the converted lines on the screen of the display.
In each of the conventional arts, various image processings such as the correction of distortion, the conversion of the viewpoint, and the reduction conversion of the obtained image are performed. Accordingly, processing load for the image processings becomes large.